Apparatus and method for managing battery

Abstract

An apparatus for managing a battery according to one embodiment of the present invention comprises: a profile acquisition unit configured to acquire a differential profile indicating a correspondence relationship between a voltage and a differential capacity of the battery; and a control unit configured to determine a first point which is, in a preset target voltage section, a starting point of the target voltage section, a second point having the highest differential capacity, and a third point having the lowest differential capacity in a voltage section equal to or greater than the voltage of the second point, and diagnose the state of the battery according to the differential capacities of the first point, the second point, and the third point.

Description

Battery management device and method

[0001] This application claims priority to Korean Patent Application No. 10-2024-0001796, filed on January 4, 2024, the entire contents of which are disclosed in the specification and drawings of the said application are incorporated herein by reference.

[0002] The present invention relates to a technology for diagnosing and managing the state of a battery, and more specifically, to a battery management device and method for diagnosing the state of a battery using the characteristics of a differential profile.

[0003] As the demand for portable electronic products such as laptops and mobile phones that use electricity as a power source increases rapidly, and as mobile robots, electric bicycles, electric carts, and electric vehicles become more widely commercialized, research into high-performance secondary batteries capable of repeated charging and discharging is actively being conducted.

[0004] Commercialized secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries have the advantage of being able to charge and discharge freely because there is almost no memory effect compared to nickel-based secondary batteries, and they have a very low self-discharge rate. In addition, they have the characteristics of high energy density and high operating voltage, so they are being studied more intensively than other types of secondary batteries and are being applied more widely in actual products.

[0005] Recently, secondary batteries are widely used not only in small devices such as portable electronic devices, but also in medium and large devices such as electric vehicles and energy storage systems (ESS).

[0006] Unlike fossil fuel-based energy generation, secondary cell-based batteries generate energy through electrochemical reactions, so as the charge-discharge cycle continues or is repeated, they cannot maintain the performance they had when they were first manufactured, that is, in the BOL (Beginning Of Life) state, and gradually deteriorate.

[0007] In this way, as batteries continue to be used (charged and discharged), their usability decreases due to deterioration in capacity and output, and their safety also becomes a risk factor. Therefore, the current status of the battery needs to be accurately diagnosed to control limited use, determine replacement timing, objectively determine prices for battery sharing or subscription, and improve the efficiency of battery reuse or recycling.

[0008] Conventional representative methods for diagnosing the condition of a battery cell include methods that utilize the behavioral characteristics of the differential profile of the battery cell or changes in peak points, and a three-electrode analysis method using a positive and negative coin half cell (CHC).

[0009] A conventional method for diagnosing whether a battery cell is degraded or not using the depth of charge, positive end potential, negative end potential, etc. is mainly used. The method involves artificially manufacturing a negative coin half cell, a positive coin half cell, etc. with a reference cell having the same specifications as the battery cell to be diagnosed, and comparing their electrical behavior characteristics with the charge / discharge profile of the target cell to determine the positions of the positive and negative electrodes corresponding to the deterioration point. Here, the reference cell refers to a cell in a BOL state and is not degraded.

[0010] However, in the case of these conventional methods, since artificial coin half cells are manufactured for each electrode, it takes a considerable amount of time, and since it is largely dependent on manual work by workers, the precision may be reduced due to various human errors such as deviations and errors.

[0011] Meanwhile, when the battery cell ages or a defect occurs during the manufacturing process, lithium plating (Li-plating) may occur, in which the lithium (Li, lithium) cations (Li+) supplied to the negative electrode are not quickly absorbed by the negative electrode and are deposited as lithium metal on the surface of the negative electrode.

[0012] In order to diagnose the occurrence of conventional lithium plating, a separate method independent of the above-described depth of charge diagnosis must be additionally applied, and therefore, diagnosing all of these requires more time and complicates the processing process.

[0013] The present invention was created to solve the above-described problems against the background described above, and aims to provide a battery management device and method capable of quickly and reliably diagnosing the current state of a battery using a differential profile of the battery.

[0014] The technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0015] A battery management device according to one aspect of the present invention may include a profile acquisition unit configured to acquire a differential profile indicating a correspondence between a voltage and a differential capacity of a battery; and a control unit configured to determine a first point, which is a starting point of a preset target voltage range, a second point at which the differential capacity is the highest, and a third point at which the differential capacity is the lowest in a voltage range higher than the voltage of the second point, and to diagnose a state of the battery based on the differential capacities of the first point, the second point, and the third point.

[0016] The control unit may be configured to calculate a first differential capacity difference between the first point and the second point, a second differential capacity difference between the second point and the third point, and a differential capacity ratio between the first differential capacity difference and the second differential capacity difference.

[0017] The control unit may be configured to compare the differential capacity ratio with a preset first threshold value and diagnose whether lithium plating of the battery has occurred based on the comparison result.

[0018] The control unit may be configured to diagnose that lithium plating has occurred in the battery if the differential capacity ratio is less than or equal to the first threshold value.

[0019] The control unit may be configured to diagnose that lithium plating has occurred in the battery when the differential capacity of the second point and the differential capacity of the third point are the same.

[0020] The control unit may be configured to determine the positive electrode potential and the negative electrode potential of the battery from the differential capacity ratio based on a potential profile preset to indicate a correspondence between the differential capacity and the positive electrode potential.

[0021] The control unit may be configured to compare the negative electrode potential with a preset second threshold value and diagnose whether lithium plating of the battery has occurred based on the comparison result.

[0022] The control unit may be configured to diagnose that lithium plating has occurred in the battery if the differential capacity ratio is less than or equal to the second threshold value.

[0023] The control unit may be configured to determine the positive electrode charge depth and the negative electrode charge depth of the battery based on the positive electrode potential and the negative electrode potential.

[0024] A battery pack according to another aspect of the present invention may include a battery management device according to one aspect of the present invention.

[0025] A vehicle according to another aspect of the present invention may include a battery management device according to one aspect of the present invention.

[0026] A battery management method according to another aspect of the present invention may include a profile acquisition step of acquiring a differential profile indicating a correspondence between a voltage and a differential capacity of a battery; a point determination step of determining a first point, which is a starting point of a preset target voltage range, a second point at which the differential capacity is the highest, and a third point at which the differential capacity is the lowest in a voltage range higher than the voltage of the second point; and a diagnosis step of diagnosing a state of the battery based on the differential capacities of the first point, the second point, and the third point.

[0027] According to one embodiment of the present invention, the battery management device has the advantage of being able to diagnose the current state of the battery in a non-destructive manner by comparing the differential capacities of points included in the differential profile of the battery.

[0028] In particular, the battery management device has the advantage of being able to specifically diagnose whether lithium plating has occurred in the battery and the depth of charge of the battery.

[0029] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0030] The following drawings attached to this specification serve to further understand the technical idea of ​​the present invention together with the detailed description of the invention described below, and therefore the present invention should not be interpreted as being limited to the matters described in such drawings.

[0031] FIG. 1 is a schematic diagram illustrating a battery management device according to one embodiment of the present invention.

[0032] FIG. 2 is a schematic diagram illustrating a first differential profile according to one embodiment of the present invention.

[0033] Figure 3 is an enlarged view of the first differential profile of Figure 2.

[0034] FIG. 4 is a schematic diagram illustrating a second differential profile according to one embodiment of the present invention.

[0035] Figure 5 is an enlarged view of the second differential profile of Figure 4.

[0036] FIG. 6 is a diagram schematically illustrating a potential profile according to one embodiment of the present invention.

[0037] FIG. 7 is a diagram illustrating an exemplary configuration of a battery pack including a battery management device according to one embodiment of the present invention.

[0038] FIG. 8 is a schematic drawing of a vehicle according to another embodiment of the present invention.

[0039] FIG. 9 is a diagram schematically illustrating a battery management method according to another embodiment of the present invention.

[0040] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner.

[0041] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0042] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0043] Terms that include ordinal numbers, such as first, second, etc., are used to distinguish one of the various components from the rest, and are not used to limit the components by such terms.

[0044] Throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise stated.

[0045] Additionally, throughout the specification, when we say that a part is "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is "indirectly connected" with other elements in between.

[0046]

[0047] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0048] FIG. 1 is a schematic diagram illustrating a battery management device (100) according to one embodiment of the present invention.

[0049] Referring to FIG. 1, the battery management device (100) may include a profile acquisition unit (110), a control unit (120), and a storage unit (130).

[0050] Here, a battery refers to a physically separate, independent cell having a negative terminal and a positive terminal. For example, a lithium-ion battery or a lithium polymer battery may be considered a battery. Furthermore, the battery may be of a cylindrical type, a prismatic type, or a pouch type. Furthermore, a battery may also refer to a battery bank, a battery module, or a battery pack in which multiple cells are connected in series and / or parallel. For convenience of explanation, the term "battery" will be described herein below as referring to a single, independent cell.

[0051] The profile acquisition unit (110) can be configured to acquire a differential profile indicating a correspondence between the voltage and differential capacity of the battery.

[0052] For example, a battery profile is a profile that represents the relationship between voltage (V) and capacity (Q) when the battery's SOC is charged from a preset start SOC or 0% to a preset end SOC or 100%. As another example, a battery profile may represent the relationship between voltage (V) and capacity (Q) when the battery's SOC is discharged from a preset start SOC or 100% to a preset end SOC or 0%.

[0053] And, by differentiating the battery profile with respect to voltage, a differential profile can be generated that represents the correspondence between the differential capacity (dQ / dV) and the voltage (V).

[0054] For example, there are no specific restrictions on the C-rate for charging or discharging to generate a battery profile. However, to obtain more accurate battery profiles and differential profiles, it is desirable to charge or discharge the battery at a low rate. For example, a battery profile can be generated during the process of charging or discharging the battery at 0.05C.

[0055] For example, the profile acquisition unit (110) can directly receive the differential profile of the battery from the outside. That is, the profile acquisition unit (110) can acquire the differential profile by receiving the differential profile through a wired and / or wireless connection to the outside.

[0056] As another example, the profile acquisition unit (110) can directly receive the battery profile of the battery from an external source. Furthermore, the profile acquisition unit (110) can differentiate the battery profile with respect to voltage to generate a differential profile. That is, the profile acquisition unit (110) can be connected to the external source via wires and / or wirelessly to receive the battery profile and directly generate a differential profile from the battery profile, thereby acquiring the differential profile.

[0057] As another example, the profile acquisition unit (110) may receive battery information regarding the voltage and capacity of the battery. Furthermore, the profile acquisition unit (110) may generate a battery profile based on the received battery information, and may generate a differential profile based on the generated battery profile. In other words, the profile acquisition unit (110) may directly generate a differential profile based on the battery information, thereby acquiring the differential profile.

[0058] The profile acquisition unit (110) may be connected to the control unit (120) so as to be able to communicate with it. For example, the profile acquisition unit (110) may be connected to the control unit (120) by wire and / or wirelessly. The profile acquisition unit may transmit the acquired differential profile to the control unit (120).

[0059] Fig. 2 is a diagram schematically illustrating a first differential profile (Pa) according to one embodiment of the present invention. In the embodiment of Fig. 2, the first differential profile (Pa) can be expressed as an XY graph in which the X-axis is set to voltage (V) and the Y-axis is set to differential capacity (dQ / dV). Specifically, the first differential profile (Pa) is a differential profile that represents a correspondence between a preset voltage and differential capacity of a first battery.

[0060] The control unit (120) may be configured to determine a first point, which is the starting point of a preset target voltage section (RT) in the differential profile, a second point having the highest differential capacity, and a third point having the lowest differential capacity in a voltage section higher than the voltage of the second point.

[0061] Here, the target voltage range (RT) is a portion of the entire voltage range of the battery, and can be preset by the control unit (120).

[0062] Specifically, the control unit (120) can determine one or more local minimum points in the differential profile. The differential profile may include one or more local minimum points. This is because the differential profile is a profile obtained by differentiating the battery profile with respect to voltage, and the slope of the battery profile (the rate of change of voltage and capacity) is not a constant.

[0063] For example, in the embodiment of FIG. 2, the first differential profile (Pa) may include a first minimum point (m1), a second minimum point (m2), a third minimum point (m3), and a fourth minimum point (m4).

[0064] And, the control unit (120) can determine a minimum point whose voltage corresponds to a preset reference voltage among one or more determined minimum points as a target minimum point.

[0065] Specifically, the control unit (120) may determine, among one or more local minimum points, a local minimum point whose corresponding voltage is near the reference voltage as the target local minimum point. In other words, the control unit (120) may determine, among one or more local minimum points, a local minimum point whose corresponding voltage is closest to the reference voltage as the target local minimum point.

[0066] For example, in the embodiment of Fig. 2, it is assumed that the reference voltage is preset to 4.0 [V]. The control unit (120) determines that among the four minimum points (m1, m2, m3, m4) included in the first differential profile (Pa), the minimum point whose corresponding voltage is closest to the reference voltage is the third minimum point (m3). Therefore, the control unit (120) can determine the third minimum point (m3) as the target minimum point.

[0067] Finally, the control unit (120) can set a voltage section higher than the target voltage corresponding to the target minimum point among the entire voltage section as the target voltage section (RT).

[0068] Specifically, the control unit (120) can set the lower limit of the target voltage range (RT) to the target voltage of the target minimum point, and can set the upper limit of the target voltage range (RT) to the upper limit of the entire voltage range of the battery. That is, the control unit (120) can set a voltage range higher than the target voltage as the target voltage range (RT).

[0069] For example, in the embodiment of FIG. 2, the target voltage (VT) is 4.06 [V]. The control unit (120) can set a voltage range of 4.06 [V] or more and 4.2 [V] or less as the target voltage range (RT).

[0070] Fig. 3 is an enlarged view of the first differential profile (Pa) of Fig. 2. Specifically, Fig. 3 is an enlarged view of the target voltage section (RT) of the first differential profile (Pa).

[0071] In the embodiment of FIG. 3, the control unit (120) may determine the starting point of the target voltage section (RT) as the first point (Pa1). That is, the first point (Pa1) may be a target minimum point included in the first differential profile (Pa). Then, the control unit (120) may determine the point with the largest differential capacitance in the target voltage section (RT) as the second point (Pa2). Finally, the control unit (120) may determine the third point (Pa3) with the smallest corresponding differential capacitance in a voltage section in which the corresponding voltage is higher than or equal to the voltage of the second point (Pa2).

[0072] In the embodiment of FIG. 3, the second point (Pa2) is a maximum point included in the target voltage section (RT), but depending on the embodiment, the target voltage section (RT) may not include a maximum point. That is, the differential capacity may not decrease in the voltage section after the first point (Pa1). For example, the rate of change of the differential capacity with respect to the voltage in the voltage section after the first point (Pa1) may be 0 or greater. In this case, the second point (Pa2) may be determined as the point at which the differential capacity is the largest in the target voltage section (RT). In addition, the differential capacity of the third point (Pa3) may be equal to the differential capacity of the second point (Pa2).

[0073] The control unit (120) can be configured to diagnose the state of the battery according to the differential capacities of the first point, the second point, and the third point.

[0074] Specifically, the differential capacity is the capacity differentiated with respect to the voltage, and represents the instantaneous rate of change of the capacity with respect to the voltage. In other words, the differential capacity is a representative factor that can also detect sensitive state changes of the battery. In particular, as the battery deteriorates, the differential capacity of the third point may change more rapidly than the differential capacities of the first and second points. For example, as the battery deteriorates, the degree to which the differential capacity of the third point increases may be greater than the degree to which the differential capacities of the first and second points decrease. Therefore, the control unit (120) can non-destructively diagnose the current state of the battery by diagnosing the state of the battery based on the differential capacities of the first to third points.

[0075] For example, the control unit (120) can diagnose whether lithium plating has occurred in the battery based on the differential capacity of the first to third points.

[0076] As another example, the control unit (120) can determine the depth of charge (DOC) of the battery based on the differential capacitance of the first to third points. Here, the DOC is an indicator of the battery's charging performance and is a term that indicates the battery's energy storage performance. For example, the higher the DOC of the battery, the more energy can be stored in the battery. Preferably, the control unit (120) can diagnose the current state of the battery more specifically by non-destructively diagnosing the positive and negative DOC of the battery.

[0077] A battery management device (100) according to one embodiment of the present invention has the advantage of being able to specifically diagnose the current state of a battery in a non-destructive manner by comparing the differential capacities of three points of a differential profile. In particular, the battery management device (100) has the advantage of being able to specifically diagnose whether lithium plating has occurred in the battery and the depth of charge of the battery.

[0078]

[0079] Meanwhile, the control unit (120) provided in the battery management device (100) may optionally include a processor, an application-specific integrated circuit (ASIC), another chipset, a logic circuit, a register, a communication modem, a data processing device, etc. known in the art to execute various control logics performed in the present invention. In addition, when the control logic is implemented in software, the control unit (120) may be implemented as a set of program modules. At this time, the program modules may be stored in a memory and executed by the control unit (120). The memory may be located inside or outside the control unit (120) and may be connected to the control unit (120) by various well-known means.

[0080] In addition, the battery management device (100) may further include a storage unit (130). The storage unit (130) may store data or programs required for each component of the battery management device (100) to perform operations and functions, or data generated in the process of performing operations and functions. The storage unit (130) is not particularly limited in type as long as it is a known information storage means known to be capable of recording, erasing, updating, and reading data. As an example, the information storage means may include RAM, flash memory, ROM, EEPROM, registers, etc. In addition, the storage unit (130) may store program codes defining processes executable by the control unit (120).

[0081] For example, the profiles acquired by the profile acquisition unit (110) can be stored in the storage unit (130). Then, the control unit (120) can access the storage unit (130) and acquire the stored profiles.

[0082]

[0083] Below, an embodiment in which the control unit (120) diagnoses whether lithium plating has occurred in the battery based on the differential capacity of the first to third points is specifically described.

[0084] The control unit (120) may be configured to calculate a first differential capacity difference for the first point and the second point. In addition, the control unit (120) may be configured to calculate a second differential capacity difference for the second point and the third point.

[0085] For example, in the embodiment of FIG. 3, the differential capacity difference between the first point and the second point is Da1, and the differential capacity difference between the second point and the third point is Da2.

[0086] The control unit (120) can be configured to calculate a differential capacity ratio for the first differential capacity difference and the second differential capacity difference.

[0087] Specifically, the control unit (120) can calculate the value obtained by dividing the second differential capacity difference by the first differential capacity difference as the differential capacity ratio. For example, in the embodiment of FIG. 3, the control unit (120) can calculate the differential capacity ratio by calculating the formula “Da2÷Da1” or “Da2÷Da1×100.” The differential capacity ratio can be expressed as a value of 0 to 1 or a value of 0% to 100% depending on the calculation formula. Hereinafter, for convenience of explanation, it is described that the differential capacity ratio is expressed as a value of 0% to 100%.

[0088] The control unit (120) may be configured to compare the differential capacity ratio with a preset first threshold value.

[0089] Here, the first threshold value may be preset to a value corresponding to the differential capacity ratio of the battery in which lithium plating has occurred. For example, the first threshold value may be preset to a value greater than or equal to 0% and less than or equal to 1%. Preferably, the first threshold value may be preset to a value greater than or equal to 0% and less than or equal to 0.5%. More preferably, the first threshold value may be preset to 0.2%.

[0090] Specifically, the control unit (120) can compare the magnitude of the differential capacity ratio and the first threshold value. That is, the control unit (120) can determine whether the differential capacity ratio is less than or equal to the first threshold value or whether the differential capacity ratio exceeds the first threshold value.

[0091] For example, in the embodiments of FIGS. 2 and 3, the differential capacity ratio of the first battery is 76%. The control unit (120) can determine that the differential capacity ratio (76%) of the first battery is greater than or equal to the first threshold value (0.2%).

[0092] The control unit (120) may be configured to diagnose whether lithium plating of the battery has occurred based on the comparison result.

[0093] Specifically, the control unit (120) may be configured to diagnose that lithium plating has occurred in the battery if the differential capacity ratio is below a first threshold value.

[0094] In the above embodiment, since the differential capacity ratio (76%) of the first battery is greater than or equal to the first threshold value (0.2%), the control unit (120) can diagnose that lithium plating has not occurred in the first battery.

[0095] As previously explained, as the battery deteriorates, the change in differential capacity at the third point may be greater than the change in differential capacity at the first and second points. In other words, if the battery's condition changes to the extent that the differential capacity ratio falls below the first threshold, lithium metal can be diagnosed as having been deposited on the battery's negative electrode surface without disassembling the battery.

[0096] The battery management device (100) has the advantage of being able to non-destructively diagnose whether lithium plating has occurred in the battery based on the differential capacity ratio between some points in the differential profile.

[0097] In particular, according to the present invention, the condition of a battery can be diagnosed simply by analyzing the profile for the target voltage section (RT) among the differential profiles. Therefore, the battery management device (100) has the advantage of being able to diagnose the condition of the battery more quickly and using fewer system resources than when analyzing the entire differential profile.

[0098]

[0099] Meanwhile, the control unit (120) may be configured to diagnose that lithium plating has occurred in the battery when the differential capacity of the second point and the differential capacity of the third point are the same.

[0100] As previously explained, depending on the embodiment, the second point may not be a local maximum. In this case, the second point may be determined as the point corresponding to the highest differential capacitance in the target voltage range (RT). Furthermore, since the second point is not a local maximum, the differential capacitance of the third point may be identical to the differential capacitance of the second point.

[0101] For example, if no maximum point appears in the target voltage range (RT), the second and third points may be the same. In this case, the voltages at the second and third points are the upper limits of the target voltage range (RT), and the differential capacitance is the highest differential capacitance of the target voltage range (RT).

[0102] As another example, if no maximum point appears in the target voltage range (RT), the second and third points may be different, but their differential capacitances may be the same. Specifically, if the differential capacitances in the voltage range after the second point are all the same, the second and third points may be different. In this case, the voltage of the second point (e.g., 4.15 [V]) and the voltage of the third point (e.g., 4.2 [V]) are different, but the differential capacitances of the second and third points are the highest differential capacitances in the target voltage range (RT).

[0103] If the differential capacities of the second and third points are the same, the control unit (120) can calculate the second differential capacity difference as 0. And, since the second differential capacity difference is 0, the control unit (120) can calculate the differential capacity ratio as 0. In this case, since the differential capacity ratio is always below the first threshold value, the control unit (120) can be configured to diagnose that lithium plating has occurred in the battery.

[0104]

[0105] Fig. 4 is a schematic diagram illustrating a second differential profile (Pb) according to one embodiment of the present invention. In the embodiment of Fig. 4, the second differential profile (Pb) can be expressed as an XY graph in which the X-axis is set to voltage (V) and the Y-axis is set to differential capacity (dQ / dV). Specifically, the second differential profile (Pb) is a differential profile that represents a correspondence between a preset voltage and differential capacity of a second battery.

[0106] In the embodiment of Fig. 4, the second differential profile (Pb) may include first to fourth minimum points (m1, m2, m3, m4). Since the voltage of the third minimum point (m3) is closest to the preset reference voltage (4 [V]), the control unit (120) may determine the third minimum point (m3) as a target minimum point. The target voltage (VT) corresponding to the target minimum point is 4.06 [V]. Accordingly, the control unit (120) may set a voltage range of 4.06 [V] or more and 4.2 [V] or less as the target voltage range (RT).

[0107] Fig. 5 is an enlarged view of the second differential profile (Pb) of Fig. 4. Specifically, Fig. 5 is an enlarged view of the target voltage section (RT) of the second differential profile (Pb).

[0108] In the embodiment of FIG. 5, the control unit (120) may determine the starting point of a preset target voltage section (RT) in the differential profile as a first point (Pb1). Then, the control unit (120) may determine the point with the largest differential capacitance in the target voltage section (RT) as a second point (Pb2). Finally, the control unit (120) may determine the point with the smallest corresponding differential capacitance in a voltage section higher than the voltage of the second point (Pb2) as a third point (Pb3).

[0109] In addition, the control unit (120) can calculate a first differential capacity difference (Db1) between the first point and the second point, calculate a second differential capacity difference (Db2) between the second point and the third point, and calculate a differential capacity ratio of the second differential capacity difference (Db2) to the first differential capacity difference (Db1).

[0110] Finally, the control unit (120) can diagnose the status of the second battery based on the calculated differential capacity ratio.

[0111] For example, in the embodiments of FIGS. 4 and 5, the differential capacity ratio of the second battery is 42%. The control unit (120) can determine that the differential capacity ratio (42%) of the second battery is greater than or equal to the first threshold value (0.2%). Accordingly, the control unit (120) can diagnose that lithium plating has not occurred in the second battery.

[0112]

[0113] Below, an embodiment in which the control unit (120) determines the positive and negative charge depth of the battery based on the differential capacity of the first to third points is specifically described.

[0114] The control unit (120) may be configured to determine the positive electrode potential and the negative electrode potential of the battery from the differential capacity ratio based on a potential profile preset to indicate a correspondence between the differential capacity and the positive and negative electrode potentials.

[0115] Here, the potential profile can be preset to indicate the correspondence between the differential capacity ratio, the positive electrode potential, and the negative electrode potential. Specifically, the positive electrode potential and the negative electrode potential corresponding to the differential capacity ratio of the battery can be determined in advance through experiments using a three-electrode cell or a coin half cell (CHC). The control unit (120) can determine the positive electrode potential and the negative electrode potential corresponding to the calculated differential capacity ratio for the battery by referring to the preset potential profile.

[0116] Fig. 6 is a diagram schematically illustrating a potential profile according to one embodiment of the present invention. Specifically, the potential profile of Fig. 6 is a potential profile preset to correspond to a battery having a charge termination voltage (or upper limit voltage) of 4.2 [V].

[0117] Referring to the previous example, the differential capacity ratio of the first battery was calculated as 76%, and the differential capacity ratio of the second battery was calculated as 42%. The control unit (120) may determine the positive electrode potential of the first battery as 4.2335 [V], and the negative electrode potential as 0.0335 [V]. In addition, the control unit (120) may determine the positive electrode potential of the second battery as 4.2175 [V], and the negative electrode potential as 0.0175 [V].

[0118] Specifically, the control unit (120) may be configured to determine the positive electrode charge depth and the negative electrode charge depth of the battery based on the positive electrode potential and the negative electrode potential.

[0119] For example, the first battery can be charged until the positive electrode potential reaches 4.2335 [V] and the negative electrode potential reaches 0.0335 [V]. The control unit (120) can calculate the positive electrode charge amount until the positive electrode potential reaches 4.2335 [V] by referring to the positive electrode profile corresponding to the first battery. Then, the control unit (120) can determine the calculated positive electrode charge amount as the positive electrode charge depth. Similarly, the control unit (120) can calculate the negative electrode charge amount until the negative electrode potential reaches 0.0335 [V] by referring to the negative electrode profile corresponding to the first battery. Then, the control unit (120) can determine the calculated negative electrode charge amount as the negative electrode charge depth.

[0120] Here, the positive electrode profile corresponding to the battery is a profile representing the current positive electrode state of the battery, and can represent the correspondence between the positive electrode capacity and the positive electrode potential. For example, a preset reference positive electrode profile is provided for a battery in the beginning of life (BOL) state or a theoretically ideal reference cell, and the positive electrode profile can be prepared by adjusting (or fitting) the reference positive electrode profile to correspond to the current state of the battery. Similarly, the negative electrode profile corresponding to the battery is a profile representing the current negative electrode state of the battery, and can represent the correspondence between the negative electrode capacity and the negative electrode potential. For example, a preset reference negative electrode profile is provided for a battery in the beginning of life (BOL) state or a theoretically ideal reference cell, and the negative electrode profile can be prepared by adjusting (or fitting) the reference negative electrode profile to correspond to the current state of the battery. Since the adjustment process of the reference positive electrode profile and the reference negative electrode profile can be applied in a conventional manner, a detailed description thereof will be omitted.

[0121] A battery management device (100) according to one embodiment of the present invention has the advantage of being able to diagnose the current state of a battery from various aspects by determining the positive and negative electrode potentials and the positive and negative electrode charge depths based on the differential capacity ratio. That is, according to the present invention, since specific information about the positive and negative electrodes is provided in addition to whether lithium plating has occurred, the state of the battery can be objectively diagnosed based on various pieces of information.

[0122]

[0123] Meanwhile, the control unit (120) may be configured to compare the cathode potential with a preset second threshold value.

[0124] Here, the second threshold value may be preset to a value corresponding to the negative electrode potential of the battery in which lithium plating occurs. In general, it is known that lithium electrodeposition reaction occurs when the negative electrode potential is lower than a predetermined value. That is, when the negative electrode potential decreases below the second threshold value, a lithium plating phenomenon may occur. For example, the second threshold value may be preset to a value lower than or equal to 0 [V]. Preferably, the second threshold value may be preset to a value lower than or equal to -0.1 [V]. More preferably, the second threshold value may be preset to -0.1 [V]. Hereinafter, for convenience of explanation, the second threshold value is described as being -0.1 [V].

[0125] Specifically, the control unit (120) can compare the magnitude of the negative potential and the second threshold value. That is, the control unit (120) can determine whether the negative potential is less than or equal to the second threshold value or whether the negative potential exceeds the second threshold value.

[0126] For example, in the embodiment of Fig. 6, the negative potential of the first battery is 0.0335 [V], and the negative potential of the second battery is 0.0175 [V]. The control unit (120) can determine that both the negative potentials of the first battery and the second battery are equal to or higher than the second threshold value (-0.1 [V]).

[0127] The control unit (120) may be configured to diagnose whether lithium plating has occurred in the battery based on the comparison results. That is, the control unit (120) may diagnose whether lithium plating has occurred in the battery using not only the differential capacity ratio of the battery but also the cathode potential.

[0128] Specifically, the control unit (120) may be configured to diagnose that lithium plating has occurred in the battery if the differential capacity ratio is less than or equal to a second threshold value.

[0129] In the above embodiment, since the negative electrode potential (0.0335 [V]) of the first battery is greater than or equal to the second threshold value (-0.1 [V]), the control unit (120) can diagnose that lithium plating has not occurred in the first battery. In addition, since the negative electrode potential (0.0175 [V]) of the second battery is greater than or equal to the second threshold value (-0.1 [V]), the control unit (120) can diagnose that lithium plating has not occurred in the second battery.

[0130] That is, the battery management device (100) can diagnose the state of the battery more objectively and complementarily by diagnosing the state of the battery based on the differential capacity ratio and / or the negative electrode potential.

[0131]

[0132] The battery management device (100) according to the present invention can be applied to a BMS (Battery Management System). That is, the BMS according to the present invention can include the battery management device (100) described above. In this configuration, at least some of the components of the battery management device (100) can be implemented by supplementing or adding to the functions of the components included in a conventional BMS. For example, the profile acquisition unit (110), the control unit (120), and the storage unit (130) of the battery management device (100) can be implemented as components of the BMS.

[0133] Additionally, the battery management device (100) according to the present invention may be provided in a battery pack. That is, the battery pack according to the present invention may include the battery management device (100) described above and one or more battery cells. Additionally, the battery pack may further include electrical components (relays, fuses, etc.) and a case.

[0134] FIG. 7 is a drawing illustrating an exemplary configuration of a battery pack including a battery management device (100) according to one embodiment of the present invention.

[0135] The positive terminal of the battery (11) can be connected to the positive terminal (P+) of the battery pack (10), and the negative terminal of the battery (11) can be connected to the negative terminal (P-) of the battery pack (10).

[0136] The measuring unit (12) can be connected to a first sensing line (SL1), a second sensing line (SL2), and a third sensing line (SL3). Specifically, the measuring unit (12) can be connected to a positive terminal of the battery (11) through the first sensing line (SL1), and can be connected to a negative terminal of the battery (11) through the second sensing line (SL2). The measuring unit (12) can measure the voltage of the battery (11) based on the voltage measured at each of the first sensing line (SL1) and the second sensing line (SL2).

[0137] And, the measuring unit (12) can be connected to the current measuring unit (A) through the third sensing line (SL3). For example, the current measuring unit (A) can be an ammeter or a shunt resistor capable of measuring the charging current and discharging current of the battery (11). The measuring unit (12) can measure the charging current of the battery (11) through the third sensing line (SL3) to calculate the charging amount. In addition, the measuring unit (12) can measure the discharging current of the battery (11) through the third sensing line (SL3) to calculate the discharging amount.

[0138] For example, the profile acquisition unit (110) can receive a differential profile indicating a correspondence between the voltage and differential capacity of the battery (11) from the measurement unit (12).

[0139] As another example, the profile acquisition unit (110) can receive a battery profile indicating a correspondence between the voltage and capacity of the battery (11) from the measurement unit (12). In addition, the profile acquisition unit (110) can differentiate the battery profile with respect to the voltage to generate a differential profile.

[0140] As another example, the profile acquisition unit (110) can receive battery information about the voltage and capacity of the battery (11) from the measurement unit (12). Then, the profile acquisition unit (110) can generate a battery profile and a differential profile from the received battery information.

[0141] An external device may be connected to the positive terminal (P+) and negative terminal (P-) of the battery pack (10). For example, the external device may be a charging device or a load. In addition, the positive terminal of the battery (11), the positive terminal (P+) of the battery pack (10), the external device, the negative terminal (P-) of the battery pack (10), and the negative terminal of the battery (11) may be electrically connected.

[0142]

[0143] FIG. 8 is a schematic drawing of a vehicle (700) according to another embodiment of the present invention.

[0144] Referring to FIG. 8, a battery pack according to an embodiment of the present invention may be included in a vehicle (800), such as an electric vehicle (EV) or a hybrid vehicle (HV). Furthermore, the battery pack (810) may drive the vehicle (800) by supplying power to a motor through an inverter provided in the vehicle (800). Here, the battery pack (810) may include a battery management device (100). That is, the vehicle (800) may include a battery management device (100). In this case, the battery management device (100) may be an onboard device included in the vehicle (800).

[0145]

[0146] FIG. 9 is a diagram schematically illustrating a battery management method according to another embodiment of the present invention.

[0147] Referring to FIG. 9, the battery management method may include a profile acquisition step (S100), a point determination step (S200), and a diagnosis step (S300).

[0148] Preferably, each step of the battery management method can be performed by a battery management device (100). In the following, for convenience of explanation, any content that overlaps with the previously described content will be omitted or briefly described.

[0149] The profile acquisition step (S100) is a step of acquiring a differential profile indicating a correspondence between the voltage and differential capacity of the battery, and can be performed by the profile acquisition unit (110).

[0150] For example, the profile acquisition unit (110) can directly receive the differential profile of the battery from the outside. That is, the profile acquisition unit (110) can acquire the differential profile by receiving the differential profile through a wired and / or wireless connection to the outside.

[0151] As another example, the profile acquisition unit (110) can directly receive the battery profile of the battery from an external source. Furthermore, the profile acquisition unit (110) can differentiate the battery profile with respect to voltage to generate a differential profile. That is, the profile acquisition unit (110) can be connected to the external source via wires and / or wirelessly to receive the battery profile and directly generate a differential profile from the battery profile, thereby acquiring the differential profile.

[0152] As another example, the profile acquisition unit (110) may receive battery information regarding the voltage and capacity of the battery. Furthermore, the profile acquisition unit (110) may generate a battery profile based on the received battery information, and may generate a differential profile based on the generated battery profile. In other words, the profile acquisition unit (110) may directly generate a differential profile based on the battery information, thereby acquiring the differential profile.

[0153] The point determination step (S200) is a step of determining a first point, which is a starting point of a preset target voltage section (RT) of a differential profile, a second point having the highest differential capacity, and a third point having the lowest differential capacity in a voltage section higher than the voltage of the second point, and can be performed by the control unit (120).

[0154] For example, in the embodiment of FIG. 3, the control unit (120) may determine the starting point of the target voltage section (RT) as the first point (Pa1). Then, the control unit (120) may determine the point with the largest differential capacitance in the target voltage section (RT) as the second point (Pa2). Finally, the control unit (120) may determine the point with the smallest corresponding differential capacitance in a voltage section higher than the voltage of the second point (Pa2) as the third point (Pa3).

[0155] As another example, in the embodiment of FIG. 5, the control unit (120) may determine the starting point of a preset target voltage section (RT) in the differential profile as the first point (Pb1). Then, the control unit (120) may determine the point with the largest differential capacitance in the target voltage section (RT) as the second point (Pb2). Finally, the control unit (120) may determine the point with the smallest corresponding differential capacitance in a voltage section higher than the voltage of the second point (Pb2) as the third point (Pb3).

[0156] The diagnosis step (S300) is a step for diagnosing the state of the battery based on the differential capacities of the first point, the second point, and the third point, and can be performed by the control unit (120).

[0157] For example, the control unit (120) can diagnose whether lithium plating has occurred in the battery based on the differential capacities of the first to third points. Specifically, the control unit (120) can be configured to calculate a first differential capacity difference between the first point and the second point, and a second differential capacity difference between the second point and the third point. In addition, the control unit (120) can be configured to calculate a differential capacity ratio for the first differential capacity difference and the second differential capacity difference. Finally, the control unit (120) can diagnose whether lithium plating has occurred in the battery based on the result of comparing the calculated differential capacity ratio with a preset first threshold value.

[0158] As another example, the control unit (120) may determine the positive electrode potential and negative electrode potential of the battery based on the calculated differential capacity ratio. Furthermore, the control unit (120) may determine the positive electrode depth of charge of the battery based on the determined positive electrode potential, and may determine the negative electrode depth of charge of the battery based on the determined negative electrode potential.

[0159] As another example, the control unit (120) can diagnose whether lithium plating has occurred in the battery based on the result of comparing the determined cathode potential with a preset second threshold value.

[0160]

[0161] The embodiments of the present invention described above are not implemented only through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded, and such implementation can be easily implemented by an expert in the technical field to which the present invention belongs based on the description of the embodiments described above.

[0162] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0163] In addition, the present invention described above is not limited to the above-described embodiments and the attached drawings, and all or part of each embodiment may be selectively combined and configured so that various modifications can be made, as those skilled in the art can make various substitutions, modifications, and changes within the scope of the technical idea of ​​the present invention.

[0164] (Explanation of symbols)

[0165] 10: Battery pack

[0166] 11: Battery

[0167] 12: Measurement section

[0168] 100: Battery management device

[0169] 110: Profile acquisition section

[0170] 120: Control unit

[0171] 130: Storage

[0172] 800: Car

[0173] 810: Battery Pack

Claims

1. A profile acquisition unit configured to acquire a differential profile indicating a correspondence between the voltage and differential capacity of the battery; and A battery management device characterized by including a control unit configured to determine a first point, which is a starting point of the target voltage range set in the differential profile, a second point having the highest differential capacity, and a third point having the lowest differential capacity in a voltage range higher than or equal to the voltage of the second point, and to diagnose the state of the battery according to the differential capacities of the first point, the second point, and the third point.

2. In paragraph 1, The above control unit, A battery management device characterized in that it is configured to calculate a first differential capacity difference between the first point and the second point, calculate a second differential capacity difference between the second point and the third point, and calculate a differential capacity ratio between the first differential capacity difference and the second differential capacity difference.

3. In paragraph 2, The above control unit, A battery management device characterized in that it is configured to compare the differential capacity ratio with a preset first threshold value and diagnose whether lithium plating of the battery has occurred based on the comparison result.

4. In paragraph 3, The above control unit, A battery management device characterized in that it is configured to diagnose that lithium plating has occurred in the battery if the differential capacity ratio is less than or equal to the first threshold value.

5. In paragraph 1, The above control unit, A battery management device characterized in that it is configured to diagnose that lithium plating has occurred in the battery when the differential capacity of the second point and the differential capacity of the third point are the same.

6. In paragraph 2, The above control unit, A battery management device characterized in that it is configured to determine the positive electrode potential and the negative electrode potential of the battery from the differential capacity ratio based on a potential profile preset to indicate a correspondence between the differential capacity and the positive electrode potential.

7. In paragraph 6, The above control unit, A battery management device characterized in that it is configured to compare the negative electrode potential with a preset second threshold value and diagnose whether lithium plating of the battery has occurred based on the comparison result.

8. In paragraph 7, The above control unit, A battery management device characterized in that it is configured to diagnose that lithium plating has occurred in the battery when the differential capacity ratio is less than or equal to the second threshold value.

9. In paragraph 6, The above control unit, A battery management device characterized in that it is configured to determine the positive electrode depth of charge and the negative electrode depth of charge of the battery based on the positive electrode potential and the negative electrode potential.

10. A battery pack comprising a battery management device according to any one of claims 1 to 9.

11. A vehicle including a battery management device according to any one of claims 1 to 9.

12. A profile acquisition step for acquiring a differential profile showing the corresponding relationship between the voltage and differential capacity of the battery; A point determination step for determining a first point, which is a starting point of the target voltage range in the preset target voltage range of the differential profile, a second point having the highest differential capacity, and a third point having the lowest differential capacity in a voltage range higher than the voltage of the second point; and A battery management method, characterized by including a diagnostic step of diagnosing the state of the battery according to the differential capacities of the first point, the second point, and the third point.

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